item

Module nu.domains.shape.item.

Leaf family: a single value in a shape fabric, with no descent below it.

Forms give the slot-level surface (read, write, observe the one value); refs bind that surface to an address. A fabric's leaves mix a value form in beside these, so the ref itself is an operand of the value it names.

Name	Sort	Call	Meaning
ItemRef	`ref`	`ItemRef(address, parent_ref=None, owner_shape=None)`	Leaf Ref: single typed value, no child descent.
MutableItemRef	`ref`	`MutableItemRef(address, parent_ref=None, owner_shape=None)`	Mutable leaf Ref: single typed value with write/erase.
ReactiveItemRef	`ref`	`ReactiveItemRef(address, parent_ref=None, owner_shape=None)`	Reactive leaf Ref: single typed value with observation.

ItemRef

Leaf Ref: single typed value, no child descent.

ItemRef(address, parent_ref=None, owner_shape=None)

Path nu.domains.shape.ItemRef. Kind Ref, sort ref, cardinality scalar.

API: exists(), missing() (from ItemForm).

Inherited methods

From nu.domains.shape.item.ItemForm:

Call	Builds	Meaning
`.exists()`	`Bool`	Whether this slot holds a value, as a `Bool`.
`.missing()`	`Bool`	Whether this slot holds no value, as a `Bool`: the negation of `exists()`.

From nu.lang.forms.Form:

Call	Builds	Meaning
`a == b`	`Bool`	Self equal to other by value: an `Eq` term, never a Python bool.
`a != b`	`Bool`	Self not equal to other by value: a `Ne` term, never a Python bool.
`.is_empty()`	`Bool`	True if this Form yields the EMPTY sentinel.
`.not_empty()`	`Bool`	True if this Form does not yield EMPTY.
`.fallback(*alternatives)`	`Self`	The first of this value and `alternatives` that is not EMPTY.

Undocumented: example.

MutableItemRef

Mutable leaf Ref: single typed value with write/erase.

MutableItemRef(address, parent_ref=None, owner_shape=None)

Path nu.domains.shape.MutableItemRef. Kind Ref, sort ref, cardinality scalar.

API: exists(), missing(), set(v), erase() (from MutableItemForm).

Inherited methods

From nu.domains.shape.item.MutableItemForm:

Call	Builds	Meaning
`.set(value)`	`SetCmd`	Build a `SetCmd`.
`.erase()`	`Erase`	Build an `Erase`.
`.init(value)`	`IfDo`	Set `value` iff the leaf is currently missing.

From nu.domains.shape.item.ItemForm:

Call	Builds	Meaning
`.exists()`	`Bool`	Whether this slot holds a value, as a `Bool`.
`.missing()`	`Bool`	Whether this slot holds no value, as a `Bool`: the negation of `exists()`.

From nu.lang.forms.Form:

Call	Builds	Meaning
`a == b`	`Bool`	Self equal to other by value: an `Eq` term, never a Python bool.
`a != b`	`Bool`	Self not equal to other by value: a `Ne` term, never a Python bool.
`.is_empty()`	`Bool`	True if this Form yields the EMPTY sentinel.
`.not_empty()`	`Bool`	True if this Form does not yield EMPTY.
`.fallback(*alternatives)`	`Self`	The first of this value and `alternatives` that is not EMPTY.

Undocumented: example.

ReactiveItemRef

Reactive leaf Ref: single typed value with observation.

ReactiveItemRef(address, parent_ref=None, owner_shape=None)

Path nu.domains.shape.ReactiveItemRef. Kind Ref, sort ref, cardinality scalar.

API: exists(), missing(), set(v), erase(), on_change() (from ReactiveItemForm).

Inherited methods

From nu.domains.shape.item.ReactiveItemForm:

Call	Builds	Meaning
`.on_change()`	`OnPrimitiveChange`	Subscribe to changes on this leaf.

From nu.domains.shape.item.MutableItemForm:

Call	Builds	Meaning
`.set(value)`	`SetCmd`	Build a `SetCmd`.
`.erase()`	`Erase`	Build an `Erase`.
`.init(value)`	`IfDo`	Set `value` iff the leaf is currently missing.

From nu.domains.shape.item.ItemForm:

Call	Builds	Meaning
`.exists()`	`Bool`	Whether this slot holds a value, as a `Bool`.
`.missing()`	`Bool`	Whether this slot holds no value, as a `Bool`: the negation of `exists()`.

From nu.lang.forms.Form:

Call	Builds	Meaning
`a == b`	`Bool`	Self equal to other by value: an `Eq` term, never a Python bool.
`a != b`	`Bool`	Self not equal to other by value: a `Ne` term, never a Python bool.
`.is_empty()`	`Bool`	True if this Form yields the EMPTY sentinel.
`.not_empty()`	`Bool`	True if this Form does not yield EMPTY.
`.fallback(*alternatives)`	`Self`	The first of this value and `alternatives` that is not EMPTY.

Undocumented: example.

item

ItemRef

MutableItemRef

ReactiveItemRef

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